If the config is missing, re-download it from Management Console again.

3. Config is present and being used by agent: check the config content itself.

Verify two things: - Console's address, bootstrap token and Certificate fingerprint are correct. Compare those in config to those on Management Console UI -> Settings.- JSON format validity, either run it through a json validator or visually check it.

Make sure that involved ports and protocols are properly configured and not-blocked. Allow this traffic through your firewalls.If you use Console's DNS name in agent's config, verify that it resolves to an available IP address for this agent.